Yucel MO et al, 2017: The Respiratory Induced Kidney Motion: Does It Really Effect the Shock Wave Lithotripsy?
Yucel MO, Ozcan S, Tirpan G, Bagcioglu M, Aydin A, Demirbas A, Karakan T.
Department of Urology, Adiyaman University , Adiyaman, Turkey.
Department of Urology, Izmir Katip Çelebi University, Izmir, Turkey.
Department of Urology, Ankara Training and Research Hospital, Ankara, Turkey.
PURPOSE: To investigate the effect of respiratory induced kidney mobility on success of shock wave lithotripsy (SWL) with an electrohydraulic lithotripter.
MATERIALS AND METHODS: Between May 2013 and April 2015, 158 patients underwent SWL treatment for kidney stones with an electrohydraulic lithotripter. The exclusion criteria were presence of a known metabolic disease (such as cystinuria), non-opaque stones, need for focusing with ultrasonography, abnormal habitus, urinary tract abnormalities, and inability to tolerate SWL until the end of the procedure. Stones greater than 20 mm, and lower pole stones were also excluded. The movement of the kidneys were measured with fluoroscopy guidance.
RESULTS: The procedure was successful in 66.7% of the males, and 56.9% of the females. The mean stone size was 11 ± 3 mm in the successful group, and it was 14 ± 4 mm in the unsuccessful group. The mean stone mobility rate was 32 ± 10 in the successful group and 40 ± 11 in the unsuccessful group. Multivariate analysis showed that stone size and kidney mobility affected the success rate significantly, however Hounsfield Unit (HU) did not.
CONCLUSION: The current study shows the significant effect of kidney motion on the success of SWL. Further studies with different lithotripters are needed to determine the significance of kidney mobility.
Urol J. 2017 Dec 25. doi: 10.22037/uj.v0i0.3774. [Epub ahead of print]
It is well recognized that respiratory movement of the kidney and stone is an obstacle to effective stone disintegration. This was also he conclusion from the measurements carried out in this study.
Different methods have been described in the literature for dealing with this shortcoming. Respiratory triggering has been attempted but was essentially without success due to difficulties to control irregular respiratory movements. Other more successful solutions comprise the use of belts or abdominal plates. High frequency ventilation can significantly reduce respiratory movement but that technique requires general anaesthesia as well as special equipment and expertise.
The mean difference in measured stone movement between the groups in this study was only 8 mm, but the range of movements was considerable with the largest distance recorded in patients treated successfully. Nothing is mentioned about the hit-rate, a variable that indeed is highly interesting. Neither is there any information on how the power level, duration of the treatment or pain experience influenced stone movement.
Although further similar studies possibly might be of some interest it might be much more rewarding to study the effect of different methods to reduce respiratory movements.
The bottom-line from the results in this report is, however, that care needs to be taken to reduce respiratory movements and to increase the shockwave hit rate. One factor of fundamental importance in this regard is certainly adequate pain treatment.